Elevator safety device



Feb. 24, 1953 o. E. MOYER 2,629,461

ELEVATOR SAFETY DEVICE Filed June 1, 1951 2 SHEETS-SHEET l INVENTOR. FC? 03cm? (5- MQYER -59 Feb. 24, 1953 O. E. MOYER 2,629,461

ELEVATOR SAFETY DEVICE Filed June 1, 1951 2 sHEETS-SI-IE 2 INVENTOR.

Patented Feb. 24, 1953 2,629,461 ELEVATOR SAFETY DEVICE Oscar E. Moyer,Zelienople', Pa., assignor to Universal Manufacturing Corp., Zelienople,Pa., a corporation of Pennsylvania.

Application June 1, 1951, Serial No. 229,383

Claims.

This invention relates to material handling elevator towers, and moreparticularly to safety apparatus to prevent the cages from falling incase the hoisting cables break.

It is among the objects of this invention to provide an elevator cagesafety device which operates automatically the moment the cage hoistingcable breaks, which requires only one operating spring, which is simplein construction and positive in operation, and which does not deform theelevator tower when it operates.

In accordance with this invention, the safety device is mounted on acage that is raised in an elevator tower by a cable and is guided byvertical rails at opposite sides of the tower. The safety deviceincludes brackets that are rigidly mounted on the upper part of the cagebeside the guide rails. Rotatable rod means extend across the cage andthrough the brackets and carry emergency brake elements that extendlaterally downward from the rod means toward the adjacent guide rails.Preferably there are two rods, one on each side of the guide rails sothat each rail is located between a pair of brake elements. An arm isfastened rigidly to each rod between the brake elements and projectslaterally away from the rod. Tension means are connected to the ends ofthe arms and extend upward and inward to the cable, to which they arerigidly connected. A spring is provided for rotating the rods in casethe cable breaks above the tension means and thereby allows the arms toswing downward. When this happens the rotation of the rods swings thebrake elements upward against the sides of the guide rails to grip therails between them in order to keep the cage from dropping in the tower.The spring is compressed between supports pivotally connected to leverarms that are secured to the rods.

The preferred embodiment of the invention is illustrated in theaccompanying drawings, in which Fig. l is a fragmentary side view of anelevator tower containing a cage provided with my safety device; Fig. 2is a plan view of the safety device; Fig. 3 is an enlarged side view ofthe safety device taken on the line III-III of Fig. 1; and Fig. 4 is acentral vertical section through the safety device after the hoistingcable has broken.

Referring to Figs. 1 and 2 of the drawings, an elevator tower has fourlegs I connected together by cross braces 2 and 3. Midway between thelegs on each of two opposite sides of the tower there is a verticalguide member or rail l attached to the inner sides of braces 2. A caseis shown being formed from a platform 6 (Fig. 2)

supported by the lower ends of upright members 1 that are connected attheir upper ends by a cross beam 8. The uprights straddle the guiderails to hold the cage in position.

Bolted to the top of the central portion of the cross beam is a U-shapebracket It, from the opposite sides of which a stirrup ll extendsupward. This stirrup is connected to the lower end of the hoisting cableI? that extends up to the top of the tower and over sheaves and down tothe hoisting engine (not shown) located beside the tower. Extendingthrough the vertical sides of the bracket are two parallel rods [3 whichare journaled in the bracket. The outer end portions of both rods arejournaled in similar brackets 14 mounted on the ends of the cage crossbeam. The rods project beyond these latter brackets on opposite sides ofvertical guide rails 4. Rigidly mounted on each end of each rod is abrake element I6 that extends downward on an incline toward the adjacentguide rail. The ends of these elements next to the rails preferably areprovided with teeth and are shaped so that if the brake elements areswung upward their teeth will frictionally engage the guide rails. Thebrake elements normally are held in their lower position, in which theyare spaced a slight distance from the guide rails, by means of arms I!rigidly connected to the two rods. The inner ends of the arms straddlethe center bracket Ill, and their outer ends are connected by shorttension lines l8 to a clamp IS on the hoisting cable a few feet abovethe cage. In normal use of the elevator the arms are inclined at such anangle as to swing the brake elements down away from the guide rails, asshown in Fig. 3.

Rigidly mounted on each rod between the sides of the center bracket area pair of upwardly extending short levers 2 I. These levers preferablyare disposed at about a right angle to the adjacent arm [1. Pivotallyconnected to the upper ends of each pair of levers by means of bolts 22is a U-shape spring support formed from a pair of parallel legs 23connected at their outer ends by a vertical plate 24. The plates 2d ofthe two spring supports support tubular bosses 26 which extendsubstantially horizontally toward each other, and a coil spring 27encircles the bosses and is supported by them. The spring is compressedbetween the two plates so that it constantly exerts pressure to forcethem away from each other.

Until the hoisting cable l2 accidentally breaks above the safety device,the brake elements l6 are held out of engagement with guide rails 4 andserve no purpose. In the event, however, that the hoisting cable breaks,it will no longer hold tension lines [8 taut, and therefore the outerends of the two arms I! can swing downward. In such an event they areswung downward very quickly and forcefully by the expanding coil spring21 pushing the two spring supports away from each other. The outwardlymoving spring supports swing the upper ends of the adjoining levers 2ioutward and thereby rotate the two rods I3 in opposite directions. Thedirections of rotation are such that the toothed brake elements I6 areswung upward into engagement with the adjoining guide rails. The forceof the spring, the weight of the arms, the leverage exerted on the brakeelements, and the weight of the cage all combin to rotate the brakeelements upward against the guide rails so that they tightly grip it andtheir teeth dig into it to prevent the cage from falling in the tower.

Due to the fact that the brake elements engage opposite sides of eachguide rail, neither the rails nor the sides of the tower are sprungoutward when the emergency brakes are applied. If the weight of theloaded cage is so great that brake elements collapse the tubular guiderails, the rails still will be gripped between the brake elements.Upward movement of the brake elements is limited by stops 28 welded tothe outer ends of the outer brackets [4. However, it would be an unusualcase where the brake elements would ever swing up against the stops,except when the safety device is not mounted on the cage. In such a casethe safety stops limit the rotation of the rods by the spring.

According to the provisions of the patent statutes, I have explained theprinciple of my invention and have illustrated and described what I nowconsider to represent its best embodiment. However, I desire to have itunderstood that, within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically illustrated anddescribed.

I claim:

1. The combination with an elevator tower in which a cage that is raisedby a cable is guided by vertical rails at opposite sides of the tower,of brackets rigidly mounted on the upper part of the cage beside saidguide rails, rotatable rod means extending across the cage and throughsaid brackets, emergency brake elements rigidly mounted on the outerends of said rod means and extending laterally downward therefrom towardthe adjacent guide rails, an arm fastened rigidly to said rod meansbetween the brake elements and projecting laterally away from saidmeans, tension means connected to the outer end of the arm and extendingupward and inward toward said cable, means rigidly connecting the upperend of said tension means to the cable, lever means rigidly fastened tosaid rod means and projecting therefrom, and a normally compressedspring for swinging said lever means to rotate said rod means in casethe cable breaks above said tension means and thereby allows the arm toswing downward, said rotation of said rod means swinging said brakeelements upward against the sides of the guide rails to keep the cagefrom dropping in the tower.

2. The combination with an elevator tower in which a cage that is raisedby a cable is guided by vertical rails at opposite sides of the tower,

of brackets rigidly mounted on the upper part of the cage beside saidguide rails, rotatable rod means extending across the cage and throughsaid brackets, emergency brake elements rigidly mounted on the outerends of said rod means and extending laterally downward therefrom towardthe adjacent guide rails, an arm fastened rigidly to said rod meansbetween the brake elements and projecting laterally away from saidmeans, tension means connected to the outer end of the arm and extendingupward and inward toward said cable, means rigidly connecting the upperend of said tension means to the cable, lever means rigidly fastened tosaid rod means and projecting therefrom, a sprin support pivotallyconnected to said lever means, and a normally compressed spring engagingthe spring support and urging it in a direction to cause said levermeans to rotate said rod means in case the cable breaks above saidtension means, said rotation of said rod means being in a direction tocause said brake elements to swingupward against the sides of the guiderails to keep the cage from dropping in the tower.

3. The combination with an elevator tower in which a cage that is raisedby a cable is guided by vertical rails at opposite sides of the tower,of brackets rigidly mounted on the upper part of the cage beside saidguide rails, a rotatable rod extending across the cage and through saidbrackets, emergency brake elements rigidly mounted on the outer ends ofsaid rod and extending laterally downward therefrom toward the adjacentguide rails, an arm fastened rigidly to the central portion of said rodand projecting laterally away from the rod, tension means connected tothe outer end of the arm and extending upward and inward toward saidcable, means rigidly connecting the upper end of said tension means tothe cable, lever means secured to the central portion of said rod andprojecting therefrom, a spring support pivotally connected to said levermeans, a coil spring having one end bearing against said support, andmeans pressing against the opposite end of the spring to compress it sothat in case the cable breaks above said tension means the spring willrotate said rod and swing said brake elements upward against the sidesof the guide rails to keep the cage from dropping in the tower.

4. The combination with an elevator tower in which a cage that is raisedby a cable is guided by vertical rails at opposite sides of the tower,of brackets rigidly mounted on the upper part of the cage beside saidguide rails, a pair of parallel rotatable rods extending across the cageand through said brackets, emergency brake elements rigidly mounted onthe outer ends of said rods and extending laterally downward therefromtoward the adjacent guide rails, a pair of arms each fastened rigidly tothe central portion of one of the rods with the two arms projecting awayfrom the rods in opposite directions, tension members connected to theouter ends of the arms and extending upward and. inward toward saidcable, means rigidly connecting the upper ends of said tension membersto the cable, lever means secured to the central portion of each rod andprojecting upward therefrom, a spring support pivotally connected to theupper end of each lever means, and a coil spring compressed between saidspring supports for pushing them away from each other to rotate the rodsin case the cable breaks above said tension members and thereby allowsthe arms to swing downward, said rotation of the rods swinging saidbrake elements upward against the sides of the guide rails to keep thecage from dropping in the tower.

5. The combination with an elevator tower in which a cage that is raisedby a cable is guided by vertical rails at opposite sides of the tower,of brackets rigidly mounted on the upper part of the cage beside saidguide rails, a pair of parallel rotatable rods extending across the cageand through said brackets, emergency brake elements rigidly mounted onthe outer ends of said rods and extending laterally downward therefromtoward the adjacent guide rails, a pair of arms each fastened rigidly tothe central portion of one of the rods with the two arms projecting awayfrom the rods in opposite directions, tension members connected to theouter ends of the arms and extending upward and inward toward saidcable, means rigidly connecting the upper ends of said tension membersto the cable, a pair of spaced parallel levers rigidly mounted on eachrod and projecting upward therefrom, a U-shape member pivotallyconnected to the upper ends OSCAR E. MOYER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 814,870 Rickavance Mar. 13, 19061,072,362 Roberts Sept. 2, 1913 1,462,382 Schonfeld July 17, 1923

